The present invention relates to a metal laminate gasket to be installed between a cylinder head and the cylinder block of an internal combustion engine, to seal therebetween. More specifically, the present invention relates to a metal laminate gasket whose secondary sealing portion is reinforced.
Recently, with the high performance of an engine, maximum explosion pressure has a tendency to rise. Especially, in a diesel engine, the maximum explosion pressure has a significant tendency to rise. On the other hand, with the reduction in weight of the engine, the mechanical strength has a tendency to decline. As a result, at the time of the explosion inside the cylinder, the lift of a cylinder head becomes large, and the following capability of a cylinder head gasket for the lift is required.
However, for example, in a conventional metal laminate cylinder head gasket wherein a primary sealing portion including a sealing bead around a combustion-chamber hole is formed, the amount of compression of the sealing bead is essentially not large compared to the lift. As a result, the following capability for the lift whose size just grew larger cannot be ensured so that an additional following capability is required. Specifically, in addition to the primary sealing portion with large heat resistance around an existing combustion-chamber hole, the secondary sealing portion with excellent following capability for a large lift of the cylinder head and excellent heat resistance is provided. Accordingly, the following capability when the cylinder head is widely lifted is required to be ensured.
Also, with the securing of the following capability of the secondary sealing portion when the cylinder head is widely lifted, it is required that load balance relative to the primary sealing portion, secondary sealing portion, and sealing portions around various types of holes such as a water hole and oil hole whose circumferences should be sealed should be appropriately distributed.
A technical problem addressed by the present invention is to provide a metal laminate gasket whose following capability relative to the lift of the cylinder head at the time of the explosion inside the cylinder is improved. Other technical problems addressed by the present invention are to provide a metal laminate gasket whose following capability when the cylinder head is largely lifted is secured by the secondary sealing portion with heat resistance and at the same time, the load balance relative to the primary sealing portion, secondary sealing portion, and the sealing portions around various types of holes whose circumferences should be sealed is appropriately distributed.
Further objects and advantages of the invention will be apparent from the following description of the invention.